Low gauge crown cap

ABSTRACT

A crown cap that may use less steel than a conventional crown cap is disclosed. A crown cap comprises a shell formed of an increased hardness, including a peripheral skirt, a round panel integrally formed with the skirt, the panel including one to three radially symmetric grooves formed therein, each groove spaced apart from a contact portion of the panel that is adapted for contacting the rim of a bottle upon application of the crown cap onto the bottle, and a liner located on the underside of the panel. The radially symmetric grooves may be circular.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Peru Patent Application No.000728-2007/OIN, filed on Jul. 6, 2007.

TECHNICAL FIELD

The technology relates to closures for containers, and more particularlyto a fluted crown cap for sealing a bottle or container opening.

BACKGROUND

The bottle cap was first patented and produced in the 1890's. The basicmetal crown cap has not conceptually changed from that time.Conventional crown caps include a circular top, a circular skirtdepending downwardly from a periphery of the top, and a downwardly andradially outwardly extending flange extending from a periphery of theskirt. The flange is fluted or serrated, and may be configured foreither pry-off or twist off removal. Upon application of the cap to abottle, the flutes are deformed to affix the cap to a bead or threads onthe bottle's finish, and a thermoformed liner on the underside of thecap is pressed against the bottle's rim to enhance sealing.

The majority of crown caps used in the U.S. are twist off types thatoperate on new bottles that are not recycled. The majority of crown capsin many countries, however, are pry-off types that often operate onrecycled bottles.

There is a general need for improved and lower weight crown caps.

SUMMARY

A lightweight, crimp-type crown cap for application to a glass beveragebottle, comprises a shell and a liner. The shell is formed of a materialcomprising steel having an average hardness of greater than 62 on the30T scale. The shell includes a panel and a peripheral skirt havingflutes downwardly depending therefrom, such that the flutes are capableof being crimped to affix the crown cap to a bottle. The panel isintegrally formed with the skirt and includes structural features formedas recesses therein. The liner is located on the underside of the panel,and includes at least one groove.

Preferably, the structural features are one to three circular grooves,and may also be a single groove, at least one of a star, a cross, one ormore circular grooves, and dimples. The grooves may be spaced apart froma contact portion of the panel such that the contact portion adapted forcontacting the rim of a bottle upon application of the crown cap ontothe bottle. The outermost groove may be aligned to the rim of aconventional bottle upon application of the crown cap to the bottle.Preferably the structure is recessed relative to the panel.

Preferably, the shell has a hardness of greater than about 65, morepreferably greater than about 68, more preferably, greater than about71, and most preferably approximately 73, and may be formed of doublereduced plate.

A combination bottle and crown cap is also provided.

A method of crimping a crown cap onto a glass bottle, comprising thesteps of providing a crown cap as described above, positioning the crowncap onto a rim of a bottle, and moving a crimping tool downwardlyrelative to the crown cap such that the crimping tool initially contactsthe crown cap only at the flutes approximately at the outer edgethereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cutaway side view depicting a crown cap embodyingaspects of the present invention;

FIG. 2A is a top plan view of the crown cap depicted in FIG. 1;

FIG. 2B is a top plan view of another embodiment of a crown cap havingreinforcement in the shape of a 5 sided star;

FIG. 2C is a top plan view of another embodiment of a crown cap havingreinforcement in the shape of a 6 sided star;

FIG. 2D is a top plan view of another embodiment of a crown cap havingreinforcement in the shape of a two-line cross;

FIG. 2E is a top plan view of another embodiment of a crown cap havingreinforcement in the shape of a four-line cross;

FIG. 2F is a top plan view of another embodiment of a crown cap havingreinforcement in the shape of plural dimples;

FIG. 3A is a partial cutaway side view depicting a embodiment of a crowncap embodying aspects of the present invention;

FIG. 3B is a top plan view of the crown cap depicted in FIG. 3A;

FIG. 3C is a perspective view of the embodiment of FIG. 3A;

FIG. 4 is a cross sectional view of the crown cap depicted in FIG. 1Bcrimped onto a bottle.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIGS. 1 and 2A to illustrate the structure and function ofan embodiment of the present invention, a crown cap 10 a includes ashell 12 a and a liner 14. Shell 12 a includes a circular panel 20 a, askirt 30, and a flange 32. Skirt 30 downwardly extends from a peripheryof panel 20 a. Flange 32 obliquely extends from skirt 30. Alternatingflutes 34 and lands 36 are formed on a circumferential portion of skirt30. Shell 12 a, and other shells shown in the figures, is shown as apry-off type that is opened with a lever. The present invention alsoencompasses a twist-off type (not shown in the figures) that is openedby twisting, as will be understood by persons familiar with crown captechnology.

Panel 20 a has two circular grooves 22 and 23 that are concentric abouta vertical center of cap 10 a. Outside of the outermost groove 23, panel20 a includes a contact portion 24 a that is adapted for contacting therim of a bottle upon application of the crown cap 10 a onto the bottle.Preferably, in its as-manufactured state as shown in FIGS. 1 and 2A,contact portion 24 a is relatively flat or has approximately the samecurvature as most of the remainder of the panel 20 a.

Each of grooves 22 and 23 preferably has an inwardly curved profile incross section, as best shown in FIG. 1, such that they function as ribsor structural reinforcements that, the inventors surmise, help tostiffen panel 20 a against deflection or deformation.

The present invention also encompasses other structural features in thepanel, such as stars, crosses, dimples, and the like. For example, FIGS.2B through 2F illustrate crowns 10 b through 10 f for examples of otherstructural features that may be employed. FIGS. 2B and 2C illustrate afive sided star 40 a and a six sided star 40 b, and FIGS. 2D and 2Eillustrate a cross 42 a formed by two lines and a cross 42 b formed byfour lines. FIG. 2F illustrates reinforcements formed by dimples 44.Preferably, the reinforcements, such as stars 40 a and 40 b and crosses42 a and 42 b, are radially symmetrical. The present inventionencompasses structure that is not symmetrical, such as interlockinggrooves (now shown in the figures). Preferably, the structure (such asgrooves, stars, crosses, dimples, and the like) formed in the panels isrecessed (that is, protrude downwardly) relative to the remainder of thepanel. The quantity, shape, and disposition of the grooves, stars,crosses, dimples and other structure may be determined by the specificperformance requirements of the crown cap, as well as its thickness,strength, ductility, intended use, and the like, which will be apparentto persons familiar with crown cap technology in light of the presentdisclosure.

Preferably, the outermost rib 23 of first embodiment 10 a and thestructures 40 a, 40 b, 42 a, 42 b, and 44 are configured to providecorresponding contact portions 24 a through 24 f, each of whichpreferably is relatively flat or has approximately the same curvature asmost of the remainder of the panel 20 a through 20 f. In each of thefigures, the contact portions 24 are located outboard of the structure23, 40 a, 40 b, 42 a, 42 b, or 44 to provide a uniform surface (that issubstantially unbeaded) on which liner 14 and the bottle rim is alignedwith such that liner 14 is located between contact portion 24 a (or 24 bthrough 24 f) and preferably deformed or squeezed in a gap therebetween.Accordingly, the shape of the contact portions 24 a through 24 fpreferably does not significantly change during the application process(including crimping) such that its shape before crimping issubstantially the same as after crimping. The present invention is notlimited to this configuration of any of the contact portions 24, butrather the scope of the invention is defined in the claims.

Skirt 30 smoothly merges into downwardly and radially outwardlyextending flange 32. The skirt 30 and flange 32 are preferably adaptedto be crimped onto the neck of a bottle for sealing The flange 32 isdivided into undulating, repeating portions that define the flutes 34and lands 36. Preferably, the repeating portions are circumferentiallyevenly spaced apart such that each flute 34 is identical to all otherflutes 34 around the circumference of the crown cap 10, and each land 36is identical to all other lands 36 around the circumference of the crowncap 10. While the crown cap 10 is shown as having twenty-one flutes 34and lands 36, it should be understood that the crown cap 10 may includeany number of flutes 34 and lands 36.

Referring to FIGS. 3A, 3B, and 3C to illustrate a second embodiment ofthe present invention, a crown cap 10′ includes a shell 12′ and a liner14. Shell 12′ includes a circular panel 20′, a skirt 30, and a flange32. Skirt 30 and flange 32 are as described above with respect to firstcap embodiment 10 a.

Panel 20′ has a single circular groove 23′ that has a center on thevertical center of cap 10′. Groove 23′ has a greater diameter than doesgroove 23 of the first embodiment (for a given crown diameter) such thatgroove 23′ is located over the bottle rim when applied, as explainedmore fully below. The embodiments of crown cap 10 a is illustrated withtwo grooves 22 and 23 and crown cap 10′ is illustrated with one groove23′. The present invention also encompasses any number of grooves,especially between one and three.

Liner 14 will be described with respect to first embodiment crown cap 10a, and the present description of liner 14 applies equally to liner 14shown with respect to embodiment crown cap 10′. Liner 14 is disposed onthe underside of panel 20 a. After crimping, liner 14 contacts and sealsagainst the rim of a bottle. Liner 14 as illustrated in FIG. 1 is aconventional, thermoformed, dual lip or bead liner that is availablefrom SACMI IMOLA, as will be understood by persons familiar with crowncap technology. The present invention is not limited to the choice orpresence of a liner, and encompasses other liner configurations, such asa conventional, single bead liner (not shown in the figures), as well asother materials, such as PVC and conventional PVC substitutes. Liner 14includes an inboard and outboard lip for contact with an inboard andoutboard portion of the bottle. The bead of a single bead linerpreferably engages the inboard portion or corner region of the bottlerim.

After any one of shells 12 a through 12 f (which are generally referredto by reference numeral 12) is formed and liner 14 is pressed into itsunderside, shell 12 is placed on a bottle finish such that the contactportion 24 is aligned with at least a portion of the rim of the bottle.Flutes 34 are crimpled or deformed about features of the bottle finishto affixed crown cap 10 to the bottle. Accordingly, upon crimping, liner14 contacts bottle rim and seals in a conventional manner.

Referring to FIG. 4 to describe the application of second embodimentshell 12′ to a bottle 50 having a rim 52 and a bead 54, after liner 14is pressed into its underside, shell 12′ is placed on a bottle finishsuch that groove 23′ is located directly over the bottle rim 52. Uponcrimping of flutes 34 relative to bead 54, liner 14 is squeezed betweenand deformed by the underside of groove 23′ and rim 52. The crimpingprocess for applying any of the shells described herein to a bottle (foreither pry-off or twist-off types of shells) preferably is performed bya ring-like crimping tool that contacts the outer edge or edge region ofthe flange 32, thereby avoiding or diminished scuffing or marring offlange 32 and diminishing force applied to bead 54.

The present invention also encompasses structure, such as single ormultiple grooves, that is located near or aligned with the inboard rimor edge of a bottle, such as bottle 50. In such a configuration, theunderside of the structure may aid in compressing or deforming the lineragainst the inboard edge or rim of the bottle (not shown in theFigures).

The crown caps 10 a through 10 f and 10′ (referred to generally byreference numeral 10) preferably are formed with steel of increasedhardness compared with conventional crown caps presently in commercialproduction. For example, conventional crown caps are often formed ofsingle reduced, T4, tinplate having a thickness of from 0.21 mm to 0.23mm. Such tinplate has an average hardness (that is, the reportedhardness value regardless of +/− variations) of approximately 61 on a30T hardness scale, in accordance with ASTM 623. Crown caps 10 describedherein may be made thinner and lighter weight compared with the priorart, for example, crown caps 10 may be formed of a material having athickness of about 0.16 mm to 0.18 mm that have the same or roughlyequal performance as conventional, thicker caps. These decreases inmetal usage are more easily achieved when the structure of crown caps 10are made with steel having increased hardness. For example, the inventorhas demonstrated the effectiveness of low gauge crowns having groovesusing DR8 (according to ASTM 623) or DR550 (according to EN 10203).Optionally, the inventor surmises that other materials may be used, suchas single reduced tinplate or like material having enhance tempering,tin-free steel having similar properties as those described herein, andthe like.

The crown caps 10 preferably have an average hardness of greater than 62on the 30T scale (conforming to ASTM 623), more preferably greater thanabout 65, more preferably greater than about 68, more preferably greaterthan about 71. The embodiments shown in FIG. 1 and FIG. 3A weredemonstrated to be effective using steel having a hardness of 73. Theupper limit of hardness is set by the maximum stress acceptable to theglass bottle during the crimping process or the spring back (which maytend to urge the crimped flanges toward an uncrimped state) associatedwith harder plate.

The crown caps 10 may be formed with conventional press equipment, withonly minor changes to parts of the tooling to form the structure (suchas the grooves, crosses, stars, and dimples). And crown caps 10 may becrimped with conventional equipment, only modified to have a smallerthroat compared with existing, conventional crimpers.

Because hardness has a relationship to strength as reflected in theyield point, the aspect of the hardness of the crown may be expressed inyield point on a corresponding scale. For example, DR8 or DR550 tinplatemay has a yield point (in a tensile test) of 550 MPA. The inventorbelieves that the most advantageous crown cap has a combination of oneor more of the structured described herein and harder plate as describedherein. The present invention, however, is stated in the claims and thepresent invention encompasses crown caps that do not have all of thestructure, materials, and/or advantages in this specification.

According to this description, commercially acceptable crown caps formedaccording to the present disclosure can be commercially made with up to25 percent less steel compared with many conventional crown caps, whichhas corresponding advantages in carbon emissions. The savings in steelweight are approximately proportionate to the reduction in metalthickness. Further, even though energy required to cool an individualcrown is tiny, the energy required to cool the total number of crownsproduced each year (approximately 45 billion in North America andapproximately 300 billion throughout the world), and the correspondingreduction in that energy, is significant.

The foregoing description is provided for the purpose of explanation andis not to be construed as limiting the invention. While the inventionhas been described with reference to preferred embodiments or preferredmethods, it is understood that the words which have been used herein arewords of description and illustration, rather than words of limitation.Furthermore, although the invention has been described herein withreference to particular structure, methods, and embodiments, theinvention is not intended to be limited to the particulars disclosedherein, as the invention extends to all structures, methods and usesthat are within the scope of the appended claims. Those skilled in therelevant art, having the benefit of the teachings of this specification,may effect numerous modifications to the invention as described herein,and changes may be made without departing from the scope and spirit ofthe invention as defined by the appended claims. Furthermore, anyfeatures of one described embodiment can be applicable to the otherembodiments described herein.

1. A lightweight, crimp-type crown cap for application to a glassbeverage bottle, comprising: a shell formed of a material comprisingsteel having an average hardness of greater than 62 on the 30T scale,including: a peripheral skirt having flutes downwardly dependingtherefrom, the flutes are capable of being crimped to affix the crowncap to a bottle; a round panel integrally formed with the skirt, thepanel including structural features formed as recesses therein; and aliner located on the underside of the panel.
 2. The crown cap of claim1, wherein the structural features are one to three circular grooves. 3.The crown cap of claim 2, wherein each groove is spaced apart from acontact portion of the panel that is adapted for contacting the rim of abottle upon application of the crown cap onto the bottle.
 4. The crowncap of claim 2, wherein the structural features includes a circulargroove that has its center approximately at the longitudinal center ofthe panel.
 5. The crown cap of claim 4, wherein the groove has adiameter to align it to the rim of a conventional bottle uponapplication of the crown cap to the bottle.
 6. The crown cap of claim 2,wherein the grooves are recessed relative to the panel.
 7. The crown capof claim 2, wherein the shell has a hardness of greater than about 65.8. The crown cap of claim 2, wherein the shell has a hardness of greaterthan about
 68. 9. The crown cap of claim 1, wherein the shell has ahardness of greater than about
 71. 10. The crown cap of claim 1, whereinthe shell has a hardness of approximately
 73. 11. The crown cap of claim1 wherein the shell is formed of double reduced plate.
 12. The crown capof claim 1, wherein the structural features include at least one of astar, a cross, one or more circular grooves, and dimples.
 13. The crowncap of claim 1, wherein the liner includes one or more beads that arecompressible to enhance sealing.
 14. A bottle and crown cap combination,comprising: a bottle having a body and a neck extending up from thebody, the top portion of the neck having a finish; a crown shell formedof material comprising steel having an average hardness of greater than62 on the 30T scale, including: a peripheral skirt having flutesdownwardly depending therefrom, the flutes are crimped on the bottlefinish to affix the crown cap to the bottle; a round panel integrallyformed with the skirt, the panel including one to three circular groovesformed therein; and a liner located on the underside of the panel. 15.The crown cap of claim 14, wherein the grooves are radially symmetricaland concentric about a center of the panel.
 16. The crown cap of claim14, wherein the grooves consist solely of a single circular groove thatis has its center approximately at the longitudinal center of the panel.17. The crown cap of claim 14, wherein the grooves are recessed relativeto the panel.
 18. The crown cap of claim 14, wherein the liner includesa pair of concentric beads that engage the bottle.
 19. The crown cap ofclaim 14, wherein the liner includes a single, plug-like lip thatengages the innermost rim of the bottle.
 20. The crown cap of claim 14,wherein bottle finish is a pry-off type.
 21. The crown cap of claim 14,wherein bottle finish is a twist-off type.
 22. A method of crimping acrown cap onto a glass bottle, comprising the steps of: providing acrown cap that includes: a shell formed of a metal having an averagehardness of greater than 62 on the 30T scale, the shell including: aperipheral skirt having flutes downwardly depending therefrom, theflutes capable of being crimped to affix the crown cap to a bottle; around panel integrally formed with the skirt, the panel includingstructural features formed as recesses therein; and the liner located onthe underside of the panel; and positioning the crown cap onto a rim ofa bottle; and moving a crimping tool downwardly relative to the crowncap, the crimping tool initially contacting the crown cap only on theflutes approximately at the outer edge thereof.